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EmDrive: the engine that breaks the laws of physics
EmDrive: the engine that breaks the laws of physics

In a major international test, the physics-defying EmDrive failed to produce the thrust that its supporters expected. In fact, in one test at the University of Dresden in Germany, it produced no thrust at all. Is this the end of all ambitions and aspirations?

How the tests of the "impossible" engine that violate the laws of physics ended

Several years ago, we wrote about this fantastic development, the creators of which threatened to turn all our ideas about space travel. EmDrive, copyrighted by its parent company SPR Ltd, in theory works by trapping microwaves in a chamber of a certain shape, where, due to the irregular shape of the chamber itself and the difference in speed, their rebound creates thrust. The chamber is closed and sealed, so from the outside it will appear that the spacecraft is simply moving without fuel or thrust.

Accumulation of this power is the main task of EmDrive, according to the company. It sounds simple, but in fact it conflicts with the current understanding of the physics of the world around us. Energy doesn't go in or out, so how do the waves get initialized, how do they keep moving, and where does their momentum come from?

EmDrive won't die so easily?

There can be no spontaneous impulse arising out of nowhere in the world without an explainable impulse, so many scientists do not take EmDrive seriously. If the engine actually works, it negates a lot of what physicists know about the universe.

However, several research groups, including NASA Eagleworks (formally known as the Advanced Physics Propulsion Laboratory, established to study new technologies) and DARPA, the US Department of Defense's research projects agency, continued to study the viability of EmDrive.

Why? “Because this concept could transform space travel and allow a spacecraft to silently rise from launch sites and go beyond the solar system,” Mike McCulloch, professor of geomatics at the University of Plymouth, UK, and DARPA EmDrive project leader, told our Western colleagues. According to the scientist, with the help of EmDrive, it is possible to make an unmanned probe reach Proxima Centauri in one human life - in about 90 years.


The essence of the EmDrive is that if the microwaves are reflected inside the chamber, they apply more force in one direction than in the other, creating pure thrust without the need for a propellant. And when NASA and the team in Xi'an tried to do it, they did have a small but distinct pure power.

Now, however, physicists at the University of Technology Dresden (TU Dresden) say that all of these promising thrust results were false positives that were attributed to external forces. The scientists recently presented their findings in three talks at the Space Propulsion Conference 2020 +1 with headlines such as "High Accuracy EmDrive Thrust Measurements and Eliminating False Positives." (Two other studies can be read here and here).

Emdrive tests

Engine operation diagram

Using a new measuring scale and different suspension points of the same engine, TU Dresden scientists "were able to reproduce apparent thrust forces similar to those measured by the NASA team, but also make them disappear with a point suspension," researcher Martin Taimar told the German website GreWi.


“When power goes to the EmDrive, the engine heats up. This also causes deformation of the fasteners on the scale, causing the scale to move to a new zero point. We were able to prevent this in a modified test model structure.Our measurements contradict all previous claims about EmDrive efficiency by at least 3 orders of magnitude."

Stakeholders described the tests as a "hit or miss" moment for EmDrive, and it looks like the outcome is leading to a complete rejection of the concept - at least for now.

DARPA has not invested too heavily in the development of the "impossible" EmDrive, and this is far from the craziest project on which the management has spent money. What's more, space travel has spawned a number of outlandish ideas for engines as scientists try to think outside the box as possible - so testing like this is the order of the day.

In this case, even negative results helped propel science forward. Taimar admitted to GreWi:

“Unfortunately, we were not able to prove any of the drive concepts, but as a result we have significantly improved the technology for measuring such objects. We can continue to research in this area of ​​science and perhaps discover something new."

It is possible that certain parts of the EmDrive technology will push scientists to a completely new concept of much more realistic and viable technologies. In addition, the scientists promised to rigorously measure other projects for false results.

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